Composite moistureproof board



Aug.5, 1924.n 1,503,957

' vo. KREss l COMPOSITE MOISTUREPROOF BQARD Filed Nov. 12. 1923 -40 like..

Inlpractice, a number ofserious objections Patented Aug; 5,1924.-

UNITED sTA-,Tes

I .1,503,957 PATENT oFFice.

erro xarss, or ArrLE'roN, WISCONSIN, Assioma ro AMERICAN LAKES rArnr comrm, A CoaroaArIoN or DELAWARE.

Comrosrra lioIsTUaEPn-oor BOARD( Application mea Navembr 12, '1923. 4serial No. 674,254.

To all whom# may concern:

Be it lmown that I, O'rro Knnss, a citizen of the United States, residing atApple? ton, county OfOuta amie, and State of Wis- 5. consin, have invente certainl new and useful Improvements in- Com osit'e Moistureproof Board, of which I eclare the 'follow- The invention consists .in the features of novelty hereinafterI described, `illustrated in the accompanying drawing, and particularly pointed out in the claims -at the end of this specification.

.In' the drawings:

. Figure 1 is a'plan view ofval sheet of moisture-proof board embodying my invention, parts'being broken away for better illustration. Figure 2 Yis an exa gerated view in vertical section of a portion ofthe sheet shown in'Fig. 1. 1 In the manufacture of moisture-proof board `intended for foi-min cartons, containers sind the'liie, it hais flsetofre llloee'n propose to em o apura't o s eets of cardboard y films of asphaltum, sheets of paper being attached to the outer faces of the\composite board by any familiar adhesive material, such as paste, glue, silicate of soda, or the have been found Ato a composite board thus made from sheets of paper board. In the first place,vv paper board cannot be made of as umform thickness asa sheet of relatively boar of asphaltum'over that necessary to combine smooth'sheets of paper together. Again, the

thick Vfilml of 'asphaltum required to unite the paper. board is brittle, will not .Hex or.

hinge readily and Willbreak down when the finished board is scored and folded to form cartons, so that the cartons are apt as sodium silicate) to the sheet,.and `theV together by interposedsheet ori inally is e fthe finis ed composite board is not., thin aper, hence the'surface of the paper is vmore or less uneven, with slight: humps and hollows .which require an excessto leak moisture at the folds. So, also, the. excess 'of asphaltum 'required in uniting sheets of paper board isapt in cold weather to cause the composite board to crack, while 111 hot weather the excess of vasphaltum tends to bleed or leak from the cut ends of the board.

It has been attempted `to overcome these dlfiiculties by applyingv the. asphaltum as a thin lilm between two thin sheets of paper and then unite the composite sheet so .formed v'to' an outer sheetof paper and to a ply or 'layer of heavy paper board by an adhesive material, such, for example, as -sodium vsilicate. In this way, it has been found possible v to 'obtain a thin, uniform, flexible film of asphalt; but althoughthis procedurev cured some o f the'diiiiculties before experienced, I have found that while the two-ply sheet made up of layers of aper united by the asphalt film is effective y moisture-proof, it

is not efficient; to prevent the passage of I moisture through the finished board',that

' is to say, through the composite board made up of such two-ply sheet united by a suitable adhesive to a heavy paper board or stiff-.

ening material, that .gives increasedbody tothesheet This is because the application of the water solution of the adhesive (such subsequent evaporation o'f the water, causes an'uneven expansion'of the paperbody of the composite sheet, which, like any paper sheet, expands when wet with water, to different degrees lengthwise and across the direction in which it passes throu h the paper machine 'on' which it is made. `o the lm of adhesive material, such as silicate of soda, contracts as it dries'.f This uneven expansion of the two-ply sheet and vthe contraction of the silicate film breaks down, at least to a considerable degree, the moisture-proofing film of asphaltv and while the two-ply lectively moisture-proof,

Again, when sodium silicate is used ,as a means for cement-ing the two-ply sheet to a sheet 4of paper that is to form theA outer contact, and in moist. weather will absorb moisture from the air. Again, the alkaline sodium silicate acts on the natural coloring agents of the paper forming the outer sheet or sheets Aor' the board andy discolors it. -While these last mentioned diliiculties will not exist if cements such as starch, glue, .dextrine orthe like be employed, stil all usuch cements must be applied in a water I0 solution and would, like thesilicate, destroy the asphalt film and materially weaken vits moisture-proofing quality,

By'the present invention, the objections hereinbefore noted are :entirely overcome. This result is accomplished primarily by 480 sheets 24 X 36 inches. Preferably, the three sheets of paper 1 2 and 3 will diier somewhat in weight, the outermost sheet 1 being preferably materially heavier than the inner sheets 2 and 3-'and weighing sayvfrom 40 to 60 pounds to the. ream, ywhile the inner sheets 2 and 3 'are preferably say between and 30 pounds to the ream; The outermost lm of asphaltum 4 may also be somewhat heavier than the film 5,- the ilm 4 running say about 2O pounds to the ream, while thelm 5 may run about 16 pounds to the ream; but the aggregate v Weight of these two layers of asphaltum 4 and 5 is much less than the weight of asphaltum heretoforming a composite. sheet consisting orl fore found necessary when the composite three layers of relatively thin paper (as distinguished from paper board) united togather by thin lms of asphaltum and this .20 compositefthree-ply sheet isthereafter cemented by silicate of soda or other `well known adhesive material, to one side of a A stifi'ening sheet, preferabl a sheet of paper board of much greater thickness and weight than the relatively thin flexible paper sheets, the paper board serving to give the requisite body to the finished product. c

lIn the embodiment of the invention illustrated in the drawing, 1, 2 and 3 designate respectively sheets of comparatively thin, and preferably hard surfaced paper, the weight 'of which may vary within a considerable range. Assuming the sheets to be 24 .X 36`inches, and with 480 sheets to the ream,

the wei ht of the paper of which the sheets 1, 2 an 3 are formed may be between 10 and 100 pounds per ream. Paper board,

as such term is understood in the trade, denotes a paper material not only of greater 40 Weight per ream for size 24 x 36 inches, but also denotes'a material the surface of which lboard is formed of sheets of paper board united together by lms of asphaltum.

The finished moisture-proofboard embodying -my present invention has the following advantages: It is of great strength and lightness and can be readily scored an folded without breaking the moisture-proof films of asphalt. Only a small amount of vasphalt is required and the lms will not crack in cold weather nor bleed orileak in warm weather. lt will also be noticed that. the three-ply sheet is quite llexible and can be readily secured toons side of the -stiiening paper board by any well known adhesive, such as silicate of soda, starch, vglue or the like, .appliedA in the form "of watered solutions. But the chieadvantage of my improved board is that the finished product is effectively moisture-proof. That is to say, cate of soda or other adhesive to one side only of the three-ply sheet will, for the vreasons stated, tend to break down the innermost film `5 of asphaltum, the outer lm 4 is protected and will not be thus' aliected. ltq

ice that while the application of siliis ordinarily much rougher and more porous will be noted that the three-ply sheet which than the paper sheets 1,2 and 3. The films is first made up is subsequently applied to of asphaltumbetween the paper sheets 1, 2 one side of the stidening board and forms, 45 and 3 are designated as 4 and 5. The three or rather its outer ply l forms, one surface vsheets of paper 1, 2 and 3 thus united toof. the finished board and preferably forms gether by the :films of asphaltum 4 and 5 the Outer surface of the cartons that will be form in eect a moisture proof sheet, which made from the board. A11 incidental adis subsequently .attached by a suitable advantage of this is that the size in the paper 50 hesive, such as a film of silicate of soda 6, forming'-the outer surface of the" carton reto a sheet of stiflening material, such as a mains-unaffected by the silicate, if silicate sheet of paper board 7, that is considerably be used, and it hence retains its water-reheavier and thicker than theI sheets or" paper sisting properties due to the size. Nor is the 1, 2.and 3 and indeed is materially heavier outer surface of the l)carton discolored by the 55 and thicker than the composite -sheet formed alkali inthe silicate of the three sheets 1, 2 and 3 of paper with if desired, the sheet of paper board 7 may the interposed films of asphaltum. The have embodied therein, in the process ci thickness, and weight of the paper board 7 formino it, gritty fillers such as china clay, will depend upon the precise weight retalc, as estine, etc. and this' material may 60 quired for the finished article. To this layer serve in cleaning the blades whereby the of paper board 7 is preferably attached, as sheets are out; or, if preferred, a like gritty by a lilm of silicate of soda 8, an inner linfiller may be embodied in the sheets of aing sheet 9 of relatively thin paper, say for per; or both the sheet of paper board9 7 example, paper weighing about 40 pounds to and the several sheets ofpaper may have @f5 the ream, assuming the ream vto consist of such gritty filler embodied therein.

Obviously, changes may be made inthe details set forth Without departin the essentials of the invention as de the claims.

' Having thus described my invention, what edl in *I claim as new and desire to secure by Letters Patent .is

1.V A composite. moisture-proof paper board comprising at least one ply of relatively heavy stifening material, and at least three cadjaeentples of relatively light paper that are iinited by. thin lms of asphalt and are unitedby a suitable adhesive to the stiffening material, substantially as described.V 2. A composite. moisture-proof paper board comprising atleast one ply of stiifen ing paper board and at least -three .adjacent plies of relatively light, smoothsurfaced,

.flexible paper, one of which forms one ofthe -outer surfaces of the finished board, the adjacent paper` pliesbeing united to one another by thin films of asphaltum and to the stilfening paper board by a suitable adhesive, substantiallyl as describeflA 3. A vcomposite moisture-proof.- board comprising at least one ply of stiffening from board and plurality of plies of paper.

united togetherby asphaltum', the said stiening* board having embodied l,therein an'.

gritty filler, lsubphalt and are united by a suitable adhesive' i to the stiiening material, an abrasive in the form of a gritty filler beingembodied in said paper or stiii'ening material. l '5. composite moisture-proof paper 'board comprising at least one, ply of stii' ening board and at least three adjacent plies bf relatively light, flexible paper united to one another by lms'ofasphaltum, one :of said plies of paper forming one of the outer surfaces ofthe finished board, the said sti'- .ening board having LAembodied therein an abrasive in the form of a gritty Eller, substantially described.' v

o'r'ro Krauss; 

